Is Glass a Liquid?

Glass...pitch...molten magma...all not quite liquid or solid...

The title says it's about glass, but the video actually is more about amorphous solids and viscosity in general. They're concepts well covered here by Dr Derek Muller of Veritasium.

Making SOLID Nitrogen!

Liquid nitrogen, sure. We have that in dewar flasks from time to time.

Gaseous nitrogen, yeah, we have that at all times around us.

Solid nitrogen, though, that we don't get to see very often.

Then along comes Dr Derek Muller of Veritasium with a better dewar and a vacuum pump to produce a gorgeous, spinning disk of solid nitrogen floating like the thinnest, coldest hovercraft in the world.

I've actually seen crystalline nitrogen in my classroom before with a far less impressive set-up that Dr Muller used. I put a 50mL beaker (or maybe a 100mL, I don't remember) in a plastic bell jar attached to a decent but not world-class vacuum pump. As the pressure dropped, the temperature dropped as well, cooling the liquid nitrogen further and eventually hitting the freezing point of nitrogen at low pressure.

The liquid nitrogen froze into a puffy, crystalline network atop the liquid. Then the liquid boiled violently, pushing the crystals out of the way and turning them back to liquid. Liquid to solid to liquid to solid...boiling then calming down again and again.

It was quite a show.

chemed 2013 diy chemistry

Alfredo Mateus is apparently pretty cool - or at least has some pretty cool ideas.

Through the Prezi above first, largely without words...

• The bottle tops - hacksawed off just below the screw top collar - become flexible in hot water and can be turned into keychains. The distorted bottle tops then can show the thermoplasticity when returned to hot water.
• The inflation of the preforms is a bit trickier, and the method hinted at in the Prezi is far tougher to pull off. Check out my other post about a way to successfully inflate the preforms.
• Carving a can with chemistry is a variation on the aluminum can demo using a solution of either sodium hydroxide or copper (II) sulfate to react away the aluminum can. Here Mateus has used this to produce some nice lights.
• The hydrophobic toys need a whole lot more explanation. The carbon compounds in soot are apparently hydrophobic and can make for a very cool 'maze' by letting the droplets roll around rather freely.
• The PET molecules, though, are pretty spectacular, and they're the ones I desperately want to recreate for my classroom. I just need to figure out how to throw around a few pop rivets. And sadly, they're the only ones that are NOT covered in the related pdf of instructions.

Any chance anybody can find better instructions for the 2L bottle molecules?

World's largest gold crystal

Wait, a single crystal of gold?

I'm familiar with single crystals of lots of other materials - silicon, titanium, copper sulfate, lots of stuff. But I've never heard of single crystals of gold.

Now we've got the largest single crystal of 217.78 grams of gold as proven by Los Alomos National Labs. Check their own website for their evidence.

LG's 1mm OLED Wallpaper TV

A friend of mine, another high school teacher told a story that when he was buying a television - maybe about ten years ago now - he met a convincing salesman. The salesman was a former student of his who remembered that the teacher had young children. When he was speaking to my friend, the salesman took his fairly heavy, full keychain and chucked it directly at the screen from about five feet away. The keychain bounced and did no damage at all. The screen - among the first flat screen, narrow depth televisions that we find so ubiquitous now - was covered with a polymer layer that made it fairly impervious to damage.

But even that wasn't a television that you could roll up and hang on the wall like it was a poster.

That's a different beast all together.

The Ship-Breakers

At low tide ship-breakers haul a 10,000-pound cable to a beached ship to winch pieces ashore as they dismantle it. (from article)

Ship-breaking...such a simple term but one that is impossibly complex.

As the National Geographic article with the simple title tells us...

Oceangoing vessels are not meant to be taken apart. They’re designed to withstand extreme forces in some of the planet’s most difficult environments, and they’re often constructed with toxic materials, such as asbestos and lead. When ships are scrapped in the developed world, the process is more strictly regulated and expensive, so the bulk of the world’s shipbreaking is done in Bangladesh, India, and Pakistan, where labor is cheap and oversight is minimal.

The process might be better titled as ship-recycling because that's what's happening with the ships, "Whatever the actual profits, they are realized by doggedly recycling more than 90 percent of each ship. ... Everything is removed and sold to salvage dealers—from enormous engines, batteries, generators, and miles of copper wiring to the crew bunks, portholes, lifeboats, and electronic dials on the bridge."

Steel from ship hulls is harvested in plates. Each can weigh a thousand pounds or more. Using brute strength and improvised rollers, teams of carriers move the plates to trucks, which transport them to mills where they are converted into steel rods for construction.

Only the problem is that the other 10%, the unrecyclable 10% is poisoning the water, the beaches, and the workers along the way to recovering the 90%.

Carriers spend their days slathered in mud contaminated with heavy metals and toxic paint particles that leach from the ships into the tidal flats.

How do we continue with this?

Is the recovery of the 90% worth the cost in environmental damages and lives shortened or lost?

The recycling rate of smartphone metals

We have to recycle more.

The issues inherent in recycling, however, are amazingly complex, most of which - by my understanding - comes to the cost of separation of the materials into individual recycling stream destinations.

It's far, far easier to recycle already separated materials, but it's tedious, dangerous, and costly to pull out every battery, screen, motherboard, chip, and plastic casing. That, apparently is why we send the task to nations where the labor laws are more lax and the labor costs far cheaper.

Thanks, as always, to the outstanding Compound Interest for the great graphic.